1. Field of the Invention
The present invention relates to an image processing apparatus which enhances the resolution of a low-resolution image and an image processing method.
2. Description of the Related Art
Recently, high-resolution televisions or displays having a large number of pixels are in widespread use. The televisions or displays convert the number of pixels of an image data into the number of pixels of a panel when displaying an image. Interpolation in which filtering is carried out with Sinc function based on the sampling theorem (cubic convolution, BiCubic method, etc.) when applying a resolution enhancement process, and a multi-frame deterioration inverse conversion method which provides images sharper than those obtained by the interpolation are known. Please see, for example, JP-A 2000-188680 (KOKAI), and “Super-Resolution Image Reconstruction: A Technical Overview” by S. Park, et al, IEEE Signal Processing Magazine, USA, IEEE, May 2003, pp. 21-36.
The multi-frame deterioration inverse conversion method is a method of resolution enhancement devised by giving an eye to the fact that a shooting object coming out in a reference frame (a frame intended to enhance the resolution) also comes out in other frames continuing therefrom and composed of the steps of detecting the movement of a shooting object in decimal accuracy, which is finer than the pixel intervals, obtaining a plurality of sample values shifted minutely in position for an identical local part of the shooting object, and modifying the pixel values successively for the plurality of sample values respectively through the interpolation in the related art.
In the multi-frame deterioration inverse conversion method, there is a problem that the quality of high-resolution image may be deteriorated because there are cases that the pixel values are modified by the sample values detected by wrong corresponding positions, and that noise component in a flat area is modified sharply.